Contemporary disposable ink cartridges typically include a self-contained ink reservoir, a jet plate assembly supporting a plurality of inkjet nozzles in combination with the ink reservoir, and a plurality of external electrical contacts for connecting the inkjet nozzles to driver circuitry. Typically, without regard to whether or not the jet plate assembly remains fully functional, the entire ink cartridge must be disposed of when the ink in the cartridge ink reservoir is completely depleted.
For thermal inkjet printer cartridges, failure is usually caused by the failure of the resistors used to heat the ink in proximity to each nozzle. However, because the resistors have such low failure rates, the typical jet plate assemblies used in disposable ink cartridges are fully operable to within their original print quality specifications even after their original ink reservoirs have been completely depleted. Thus, the contemporary disposable cartridge represents a considerable waste of product resulting in higher costs to the consumer both in product cost and the time lost in frequently replacing depleted ink cartridges.
Manually refilling the ink reservoir inside the disposable ink cartridge is a feasible option for continuing to use the cartridge as long as the print quality from the jet plate is known to be high. However, this process is messy and difficult because many disposable ink cartridges are not designed with refilling in mind. More recently, some ink cartridges have been designed to enable manual replenishment. However, this still does not mitigate the inconvenience, time, and expense involved in having to refill the ink cartridge reservoir frequently.
Automatic refilling has also been contemplated. Systems have been proposed which allow periodic refilling of the ink-jet cartridge at a "service station" provided at one extreme of print carriage movement. In addition, various schemes of continuously supplying ink to the small reservoir in the disposable inkjet cartridge from a larger reservoir located remote from the print carriage have been created. In many of these systems, the external ink reservoir, the ink cartridge, and the tubing connecting the external reservoir to the ink cartridge are configured to form a unitary single piece replaceable assembly. The volume of ink in the external reservoir is designed to be depleted when the print quality of the jet plate on the ink cartridge assembly has degraded to a level that may provide unsatisfactory printing results.
Systems such as these also have several disadvantages. They require the disposal of a large ink reservoir, an ink cartridge, and the tubing connecting the two once the ink in the large reservoir has been depleted. The waste and initial cost to the consumer therefore still exists for this type of system. In the graphic arts industry, it has also become common to use different types of inks for different applications, such as indoor and outdoor applications. With existing systems, it is very inconvenient to re-plumb a printer with new reservoirs, cartridges, and associated connecting tubing when a different ink type is required for a new print job.